The effects of the cerebral, cerebellar and vestibular systems on the head stabilization reflex.

The head stabilization reflex (HSR) is a brain stem reflex which appears in the neck muscles in response to sudden head position changes and brings the head to its previous position. The reflex mechanism has not been understood. The afferent fibers come from cervical muscle spindles, vestibular structures, and the accessory nerve, the efferents from the accessory nerve. In this study, we aim to investigate the roles of supraspinal neural structures and the vestibular system on the HSR. The patient group consisted of 86 patients (33 cerebral cortical lesion, 14 cerebellar syndrome and 39 vestibular inexcitability or hypoexcitability); the control group was composed of 32 healthy volunteers. Concentric needle electrodes were inserted into the sternocleidomastoid muscle (SCM) and the accessory nerves were stimulated with the electrical stimulator. A reflex response of about 45-55 ms was obtained from the contralateral SCM muscle. 50 % of cases had bilateral loss whereas 37 % of cases with unilateral cerebellar lesions had an ipsilateral reflex loss. Bilateral HSR loss was detected in 84 % of cases with bilateral cerebellar lesions. Bilateral reflex loss was observed in 70 % of patients with unilateral cortical lesions and 94 % of those with bilateral vestibular dysfunction. Ipsilateral HSR loss was observed in 55 % of cases with unilateral vestibular dysfunction. It was discovered that supraspinal structures and the vestibular system may have an excitatory effect on HSR. This effect may be lost in supra-segmental and vestibular dysfunctions. The localization value of HSR was found to be rather poor in our study.

Telbivudine in liver transplant recipients: Renal protection does not overcome the risk of polyneuropathy and myopathy.

The recently reported benefit of telbivudine for renal function has not been systematically studied in long-term liver transplantation (LT) recipients who are at high risk for renal impairment. We aimed to examine whether switching lamivudine therapy to telbivudine could improve renal function in LT recipients who have impaired renal function. This single-center, prospective cohort study enrolled LT recipients who were on lamivudine for hepatitis B virus (HBV) prophylaxis and who had renal impairment for at least 1 year. Lamivudine was switched to telbivudine. The primary outcome was to evaluate the change in renal function at weeks 12, 24, 36, and 48. The secondary outcomes were to assess the efficacy of telbivudine for HBV prophylaxis and the safety profile of telbivudine in the posttransplant setting. After 45 patients were enrolled, the study was terminated early because of increased rates of polyneuropathy/myopathy. During telbivudine treatment (median, 64 weeks), estimated glomerular filtration rate (eGFR) increased in 34 patients (76%). The improvement in renal function was prominent after 24 weeks of telbivudine treatment. Telbivudine was effective as prophylaxis against HBV recurrence. Twenty-six patients (58%) developed polyneuropathy and/or myopathy. The 1-year estimated incidence of polyneuropathy/myopathy was 28%. Diabetes was the strongest predictor of polyneuropathy/myopathy (hazard ratio, 4.13; 95% confidence interval, 1.49-11.50; P = 0.007). In conclusion, although it seems to have a favorable effect in the improvement of renal function and seems to be effective in the prevention of HBV recurrence, the high risk of polyneuropathy and myopathy hampers the use of telbivudine in LT recipients.

Molecular analysis in X-linked adrenoleukodystrophy patients: identification of a novel mutation.

X linked adrenoleukodystrophy (X-ALD) is a neurodegenerative disease characterized by progressive demyelination of the central nervous system, adrenocortical insufficiency and elevated levels of very long chain fatty acids (VLCFAs). It is caused by mutations in ABCD1 gene located at Xq28. More than 1,300 mutations have been identified to date which is unique to each patient. In this study we report the mutational analysis of 2 X-ALD patients (1 male and 1 female) showing variable clinical spectrum. The mutation analysis of the female patient revealed IVS5-6delC (c.1489-6delC) and p. P543L variations in compound heterozygous state. The male patient was found to be hemizygous for a novel mutation, p. R104P. In conclusion, while defining a novel mutation, the cases presented herein may contribute to the mutation and clinical spectrum of X-ALD.

What does epileptic nystagmus show us in cases presenting acute neurological symptoms?

PURPOSE: This study aims to determine the clinical significance of epileptic nystagmus in patients with acute neurological symptoms. METHOD: The clinical findings of patients with documented epileptic nystagmus, their original video and EEG data, and cranial imaging and laboratory tests were analyzed retrospectively. RESULTS: 20 patients were included in the study and 21 epileptic nystagmus attacks were determined from patients' clinical and video-EEG recordings. All recorded seizures with epileptic nystagmus were focal onset in nature. The ictal discharge pattern was rhythmic fast activity with a mean frequency of 15 Hz. The ictal discharges originated from the parieto-occipital (n = 8), temporo-occipital (n = 7), parieto-occipito-temporal (n = 3), temporal (n = 2), occipital (n = 1), and centroparietal (n = 1) areas. In the fast phase, the nystagmus was beating away from the side of ictal discharges. The origin of the ictal discharges on EEG images was compatible with the lesion localization at cranial MRI in all patients. Etiologies were epilepsy in seven patients, non-ketotic hyperglycemia in four, ketotic hyperglycemia in one, PRES in three, acute stroke in three, HSV encephalitis in one, and MELAS in one. CONCLUSIONS: Epileptic nystagmus represents a guide to the lateralization and localization of the lesion in cases presenting with acute neurological symptoms. In these patients, the lesion is frequently in the posterior regions of the hemispheres. Although various diseases affect these regions in terms of etiology, such cases should be evaluated in terms of the presence of hyperglycemia.

Vestibular impairment in Charcot-Marie-Tooth disease.

OBJECTIVE: To find out if Charcot-Marie-Tooth (CMT) patients, who have peripheral vestibular as well as peripheral somatosensory impairment, have worse postural balance than those who do not. METHODS: We studied 32 patients with various CMT phenotypes and genotypes. Vestibular function was measured with the video head impulse test (vHIT) which tests vestibulo-ocular reflex (VOR) gain from each of the six semicircular canals in response to rapid head rotations. Postural balance was evaluated with a battery of four postural tests with emphasis on the modified clinical test of sensory integration in balance (mCTSIB). RESULTS: Half of the 32 patients had some impairment of vestibular function ranging from mild, affecting only 1-2 semicircular canals, to almost total affecting all 6 semicircular canals. Their mCTSIB scores correlated with VOR gain from the vertical rather than from the lateral semicircular canals. The worse the vertical VOR gain the worse the mCTSIB score. CONCLUSION: We propose that any CMT patient could have clinically inapparent vestibular impairment that can be easily measured with the vHIT. This vestibular impairment could be contributing to their imbalance and could respond to a focused vestibular rehabilitation program.

Vestibular impairment in chronic inflammatory demyelinating polyneuropathy.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a common, treatable, autoimmune peripheral neuropathy considered to produce imbalance by weakness and proprioceptive impairment rather than vestibular impairment. We measured semicircular canal vestibular function in 21 CIDP patients (15M/6F) by the video head impulse test and postural stability with a battery comprising the modified Clinical Test of Sensory Integration and Balance, the Berg Balance Scale, the Dynamic Gait Index, the Fall Efficiency Scale, and the International Cooperative Ataxia Rating Scale. Of the 21 patients, 16 had vestibular impairment, ranging from mild-affecting just a single semicircular canal, to severe-affecting all 6 canals. Although the severity of the vestibular impairment did not correlate either with the severity of the postural imbalance or of the peripheral neuropathy, our data show that vestibular impairment is an additional challenge to balance that some CIDP patients will face.

Sacrolumbar intersegmental reflex circuit in men and its relation to the ejaculatory process.

OBJECTIVE: We aimed to investigate electrophysiologically the intersegmental reflex circuit from sacral to lumbar cord segments in normopotent adult men, in patients with spinal cord injury and in patients with premature ejaculation. METHODS: Reflex EMG activity of the cremasteric (CM) and bulbocavernosus (BC) muscles was recorded simultaneously by needle electrodes during electrical stimulation of the upper lumbar and sacral dermatomes, respectively. Thirty-three healthy male volunteers, 16 patients with spinal cord injury (SCI) at the thoracic or cervical levels, and 26 men with premature ejaculation (PME) were included in the study. RESULTS: In controls, upper lumbar dermatomal stimulation (ULS) at the inner side of thigh only elicited a reflex response from the CM muscle and did not produce a regular response from the lower sacral myotomes such as in the BC muscle. However lower sacral dermatomal stimulation (LSS) at the dorsal nerve of penis consistently evoked reflex responses from both CM and BC muscles. These basic electrophysiological features were not different in patients with SCI. LSS did not elicit a reflex response from the CM muscle in about 39% of patients with PME, while the BC reflex was obtained from all patients with PME. CONCLUSIONS: The neurophysiological pattern in BC and CM muscles during sacral or lumbar dermatomal stimulation reflects the sacrolumbar intersegmental reflex linkage that may be related to the ejaculatory process in men. The intersegmental sacrolumbar reflex circuit may be functionally disturbed in some patients with PME. SIGNIFICANCE: Interaction between the reflex activity of sacral to lumbar dermatomes could prove useful in defining electrophysiological mechanisms related to ejaculation in men.

Anesthetic management of Guillain-Barré syndrome in pregnancy.

We report the case of a 23-year-old woman who was diagnosed with an axonal type of Guillain-Barré syndrome at 16 weeks' gestation. The patient had severe motor loss but she was treated effectively with intravenous immunoglobulin, and she underwent cesarean delivery with epidural anesthesia at full term.

Cutaneous silent periods of the vastus medialis evoked by the stimulation of lateral femoral cutaneous nerve.

OBJECTIVE: Cutaneous silent period (CSP), which is a spinal reflex mediated by A-delta cutaneous afferents, is transient suppression of the electromyographic activity. In this study, our aim is to investigate CSPs of vastus medialis muscle (vm-CSP) evoked by the stimulation of the lateral femoral cutaneous nerve (LFCN) in healthy controls and in patients with meralgia paresthetica (MP). METHODS: Twenty-one patients with MP (17 unilateral, 4 bilateral) and 27 healthy controls were included. Nerve conduction studies of LFCN and vm-CSP were analyzed in all subjects. A stimulus train consisting of five electrical shocks was applied to the skin at the anterolateral side of the thigh for recording of the vm-CSP. RESULTS: Nerve conduction abnormalities of LFCN were observed in all patients with MP. Mean duration of vm-CSP was 69.7+/-9.2ms, and mean onset latency was 44.7+/-6.9 in healthy controls. Onset latency of vm-CSP was significantly prolonged and the duration of vm-CSP was significantly shortened in patients with MP. Vm-CSP abnormalities were observed in 20/25 extremities with MP. CONCLUSIONS: Dysfunction of A-delta afferents may cause these findings in patients with MP. Additionally, spinal modulation of pain may also play a role in the explanation of our findings. SIGNIFICANCE: The present study demonstrates the CSP alterations in the patients with entrapment neuropathy of a cutaneous nerve.

Myasthenia gravis and thymoma coexisting with myotonic dystrophy type 1.

We describe a 34-year old man presenting with subacute generalized myasthenic symptoms. His clinical features and laboratory investigations demonstrated both myasthenia gravis and myotonic dystrophy type 1. The computerized tomography of chest revealed anterior mediastinal mass. The lymphocyte-rich thymoma was removed surgically and he received radiotherapy. Recent observations suggested that the patients with myotonic dystrophy may have an increased risk of benign and malignant tumours but its coexistence with thymoma is very rare. The risk of thymoma associated with myotonic dystrophy is unknown.

The relationship between lower urinary tract symptoms associated with benign prostatic hyperplasia and erectile dysfunction: the role of autonomic hyperactivity.

BACKGROUND/AIM: To investigate whether autonomic nervous system (ANS) hyperactivity may be a potential cause for the relationship between lower urinary tract symptoms (LUTS) and erectile dysfunction (ED). MATERIALS AND METHODS: Twenty-four patients were recruited for this study. Complete physical examinations, urine analysis, uroflowmetry, and postvoid residual urine volume (PVRU) analysis were performed. The potential impact of some factors such as hyperglycemia, obesity, and hyperlipidemia were analyzed. These values were correlated with the various symptom scores. We performed an electromyographic and an electrocardiographic evaluation. The alterations after treatment with 2 different alpha-blockers were also analyzed. RESULTS: The electromyographic and electrocardiographic assessments revealed a minimal increase in ANS activity and it did not change significantly after treatment (P > 0.05). After treatment, maximum flow rate increased and PVRU decreased significantly (P < 0.001 and P < 0.001, respectively); total and free testosterone levels increased significantly (P = 0.0068 and P = 0.0071, respectively). There was a statistically significant difference between the 2 treatment groups regarding the outcomes of the Danish Prostate Symptom Score questionnaire (P = 0.047). CONCLUSION: This current study suggested that the effect of ANS hyperactivity is not the fundamental factor underlying the relationship between LUTS and ED.

Effects of a Dynamic Warm-Up, Static Stretching or Static Stretching with Tendon Vibration on Vertical Jump Performance and EMG Responses.

The purpose of this study was to investigate the short-term effects of static stretching, with vibration given directly over Achilles tendon, on electro-myographic (EMG) responses and vertical jump (VJ) performances. Fifteen male, college athletes voluntarily participated in this study (n=15; age: 22±4 years old; body height: 181±10 cm; body mass: 74±11 kg). All stages were completed within 90 minutes for each participant. Tendon vibration bouts lasted 30 seconds at 50 Hz for each volunteer. EMG analysis for peripheral silent period, H-reflex, H-reflex threshold, T-reflex and H/M ratio were completed for each experimental phases. EMG data were obtained from the soleus muscle in response to electro stimulation on the popliteal post tibial nerve. As expected, the dynamic warm-up (DW) increased VJ performances (p=0.004). Increased VJ performances after the DW were not statistically substantiated by the EMG findings. In addition, EMG results did not indicate that either static stretching (SS) or tendon vibration combined with static stretching (TVSS) had any detrimental or facilitation effect on vertical jump performances. In conclusion, using TVSS does not seem to facilitate warm-up effects before explosive performance.

Myoclonic status epilepticus in six patients without epilepsy.

Myoclonic status epilepticus (MSE) is defined as prolonged period of myoclonic jerks that are correlated with epileptiform discharges on EEG. We here describe clinical features and video-EEG records of six adult patients with MSE who did not have a prior diagnosis of epilepsy. In four out of six patients, MSE was precipitated by drugs. Two out of four patients had chronic renal disease and received beta lactam group antibiotics. Two other patients, who described chronic pain, developed MSE while taking pregabalin. One patient who had dementia and family history of juvenile myoclonic epilepsy (JME) developed MSE one month after quetiapine was introduced. Another patient, who had a recent ischemic stroke, developed MSE due to an unknown reason. In these last two patients, an immediate triggering factor was not evident. Myoclonic status epilepticus ceased in five out of six patients after withdrawal of the drugs and/or intravenous antiepileptic treatment. Myoclonic status epilepticus is a rare event in patients without epilepsy. A correct diagnosis and prompt drug discontinuation may reverse this severe and life-threatening condition.

Unilateral rhythmic testicular movements.

A male patient came to our clinic because of a continuous up and down movement of his right testis, which was present even during sleep. The nature and localization of the unilateral rhythmic cremasteric activity is investigated by electrophysiological methods. Investigations of the cremasteric muscles and genitofemoral nerve determined that the movement was similar to myokymia. The localization of this peculiar spontaneous movement is probably in motor fibers somewhere between the L1-L2 motor neuron pool, motor roots and/or the genitofemoral nerve.

Sensory nerve conduction in branches of common interdigital nerves: a new technique for normal controls and patients with morton's neuroma.

In this article, a new electrodiagnostic approach is described for patients with Morton's neuroma. The new method is based on the anatomic fact that the two branches of the common plantar interdigital nerves innervate the lateral side of one toe and the medial side the next one. This study included 20 normal subjects (aged 28-58 years, 10 men and 10 women) and 4 patients with Morton's neuroma (aged 44-52 years, 4 women). The branches of adjacent common plantar interdigital nerves that innerve one toe were stimulated superficially and separately with half of one toe covered with a piece of medical tape. The recordings were obtained on the posterior tibial nerve at the medial malleolus with needle electrodes. Thus, the difference in latencies of obtained sensory nerve action potentials on the posterior tibial nerve with needle electrode was measured. From normal subjects' data, it was determined that a latency difference value of above 0.17 milliseconds (mean +/- 2.5 SD) in one toe was abnormal. All of the patients with Morton's neuroma showed abnormal interlatency difference values. This new method, which we have developed, is more sensitive, simple to use, does not require extra equipment, and does not cause excessive pain. We suggest that interlatency difference between branches of the common plantar interdigital nerves is a useful and sensitive method for the diagnosis of Morton's neuroma.

Withdrawal reflexes in adductor muscles elicited by electrical and magnetic stimulation of the obturator nerve.

The withdrawal reflex in the short head of the biceps femoris muscle after electrical stimulation of the sural nerve at the ankle has been investigated in numerous studies. These studies have described two distinct responses: early (R-II) and late (R-III). However, withdrawal reflex activity of the adductor muscles in the legs has not been studied systematically. Adductor muscle reflex activity is important because it can produce serious clinical problems, such as adductor spasticity and spasms, during bladder surgery. The present study examined withdrawal reflex features of adductor muscles obtained by electrical and magnetic stimulation of the obturator nerve (ON) in 34 normal healthy subjects. Early adductor muscle withdrawal reflex responses were elicited by ipsilateral ON electrical stimulation with a mean latency of 45.7+/-2.0 ms (responses in 94% of subjects). Reflex responses were also obtained using magnetic stimulation at a similar incidence rate. Contralateral ON electrical stimulation resulted in a similar reflex, but with a lower incidence. ON and femoral nerve electrical and magnetic coil stimulation produced similar low-incidence responses in the vastus medialis. These findings indicate that short latency adductor withdrawal reflexes are easily obtained on both sides following electrical or magnetic stimulation of the ON, and they can be elicited by both nociceptive and nonnociceptive stimuli. These reflexes prepare the body for a proper response to incoming signals and likely serve to protect the pelvic floor and pelvic organs.

Morphology and innervation of the human cremaster muscle in relation to its function.

The electromyographic properties of the cremaster muscle (CM) are quite different from other skeletal muscles. It shows excessive spontaneous discharges, and the motor unit shape and firing frequency of the CM muscle differ from that of limb muscles. In this study, CM of six adult cadavers and six orchiectomy specimens were used to reveal the detailed histology of the muscle and provide an anatomophysiological explanation for these unusual electromyographic properties. Routine histochemical stains revealed the CM was composed of several distinct bundles of smooth and striated muscle fibers within connective tissue. The smooth muscle fibers that were more profuse than previously known and were not arranged in layers, but widely dispersed between striated muscle fibers. Bielschowsky silver staining technique, anti-neurofilament and anti-synaptophysin immunostaining showed the presence of multiple motor end-plates observed as a series of small dots or lines running along the striated muscle fibers and several nerve endings on a single muscle fiber. Myosin immunostaining confirmed the CM is a slow-twitch muscle, and alpha-actin smooth muscle immunostaining confirmed the presence of a large number of smooth muscle fibers. There were also small multipolar neurons forming nerve plexuses between smooth muscle fibers. Anti-GFAP immunostaining confirmed the presence of glial cells similar to astrocytes. In conclusion, the findings of this detailed anatomical study showed the CM, widely known as a striated muscle, contains a large number of smooth muscle fibers, and the spontaneous electromyographic discharges are due to the presence of multiple motor end-plates and dense innervation.

Sensory conduction study of the infrapatellar branch of the saphenous nerve.

Although neuropathies of the infrapatellar nerve (infrapatellar branch of the saphenous nerve, IPBSN) have been reported clinically, no electrophysiological method has been defined to evaluate IPBSN conduction. We therefore studied a total of 60 saphenous nerves and 60 IPBSNs from 36 volunteers. The IPBSN was stimulated medially with a surface electrode 2 cm below the patella. The response was recorded with a needle electrode located close to the nerve 1 cm lateral to the femoral artery in the inguinal region. Sensory nerve action potentials were obtained from each subject; mean latency of the first positive peak was 8.1 +/- 0.9 ms, conduction velocity was 54 +/- 4.4 m/s, and response amplitude was 1.3 +/- 1.1 microV. The method that we describe may be an easy and useful electrophysiological test for neuropathies of the IPBSN.